The invention described herein was made in the performance of work under NASA Contract No. NCC8-115 and is subject to provisions of Section 305 of the National Aeronautics and Space Act of 1958 (42 U.S.C. 2457).
1. Field of the Invention
The present invention relates to cryogenic propellant fuel tanks for air vehicles, and more particularly to a cryogenic propellant tank structure including multiple contiguous fuel containers having an overall configuration that conforms to the interior of the air vehicle, adjacent fuel containers sharing a common bulkhead structure.
2. Description of the Related Art
It is now well-known that in order to achieve a single stage to orbit reusable launch vehicle (xe2x80x9cSSTO-RLVxe2x80x9d), it is necessary to attain an extremely low vehicle mass fraction. xe2x80x9cMass fractionxe2x80x9d is a term that commonly refers to the ratio of the dry weight of a vehicle to the gross lift-off weight of the same vehicle.
Various configurations of aerospace vehicles have been proposed to achieve such an objective. For example, the prior art teaches traditional SSTO configurations of the type typically used in the NASA""s space shuttle program. These vehicles use external expendable drop fuel tanks, and examples are shown in U.S. Pat. No. 3,929,306 to Faget et al, U.S. Pat. No. 4,452,412 to von Pragenau, U.S. Pat. No. 4,557,444 to Jackson et al., and U.S. Pat. No. 4,817,890 to Coffinberry. SSTO vehicles which do not use expendable fuel tanks are also known, as evidenced by the teachings of U.S. Pat. No. 3,261,571 to Pinnes, U.S. Pat. No. 3,955,784 to Salkeld, and U.S. Pat. No. 5,975,466 to Kahara et al. In the Pinnes patent, the fuselage of an aircraft intended for orbital flight comprises a plurality of cryogenic fuel tanks arranged in a triangular configuration and secured together to form the fuselage of the craft. In the Kahara et al. patent, the aircraft disclosed includes a fuel tank, which takes the form of a collapsible bladder. And in the Salkeld patent, there is disclosed an aerospace vehicle which incorporates two different propulsion systems that are operated in sequence and which use cryogenic fuels stored in tanks within the body of the vehicle.
Against this background of known technology, the applicants have developed a novel fuel tank structure for housing and delivering disparate cryogenic fuels to combustion zones in an aerospace vehicle. The tank comprises a plurality of containers having volumes that are separated by common wall bulkheads and which are arranged substantially side-by-side in conformance with the interior of the aerospace vehicle. A tank support structure positioned within the vehicle interior includes lengthwise supports as well as cross-wise supports, with the latter including openings within which the rear ends of the containers are supported. Fuel from the containers is delivered to the vehicle""s combustion system via appropriate fuel lines carried by dome shaped end caps at the rear ends of the containers.
It is therefore an object of the present invention to provide a novel cryogenic fuel tank for an aerospace vehicle that will provide an extremely low vehicle mass fraction, while overcoming many of the disadvantages and drawbacks of similar fuel tanks known in the art.
Another object of the present invention is to provide a fuel tank for cryogenic propellants, which conform to the interior space of an air vehicle in which the tank is located.
Still another object of the invention is to provide one fuel tank within another fuel tank, the two tanks holding disparate cryogenic fuels, which are intended to be mixed before being combusted.
Yet another object of the invention is to provide a novel cryogenic propellant tank in which the overall configuration of the tank is a deltoid shape.
These and other objects, advantages and features of the invention will become more apparent, as will equivalent structures which are intended to be covered herein, with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings in which: